[Christ]

Originally Posted by dipstick

Forgive the obvious lack of experience and knowledge, but isn't FE determined by fuel consumption as determined by volume of air flow through the venturi in the throttle body in the case of a carb, and by computer in the case of injection? And in the case of injection, isn't vacuum pointless because the real issue would be the health and output of a specific sensor? Wouldn't it be better to modify the output of said sensor, perhaps the Throttle Position Sensor??? Trick the computer to believe the throttle is at a lower setting, while allowing greater air flow, thus increasing the chamber pressures and leaning the mixture and increasing power and FE?

Or did I miss something?

I think you did indeed miss something.

The vacuum gauge is a beginner modification that can be used to help transition someone into the world of instrumentation available to aide them in achieving better fuel economy.

Determining the negative pressure of the manifold will, in all accounts, be beneficial, as even with OEM EFI systems, the standard practice is that LessVacuum == MoreLoad, hence: more fuel injected to compensate.